Seventeen years ago, I was an organizer in Mississippi. And I was scared.

We were planning a march to stop the governor from turning a public, historically black university, Mississippi Valley State University in Itta Bena, into a prison. Byron De La Beckwith had just been put in prison for killing Medgar Evers -- the NAACP's field secretary in Mississippi. It was 30 years too late, but the Ku Klux Klan was still enraged that one of its own had been sentenced to prison for killing a black man. The group threatened to kill me or one of the other organizers in retaliation.

As the march approached, the threats became more numerous and specific. One night, in the cauldron of that long moment, I remembered something my parents often told me as a child: "We all get scared. The question, son, is how you respond. If you act in response to your fears, you are a coward. If you act in spite of your fears, you are courageous."

I took their words to heart. I got refocused, and I felt re-energized. The march went forward -- much larger than planned. And ultimately, the school was saved.

Many of us go through life believing America's age of martyrs ended when Dr. Martin Luther King Jr. was assassinated on April 4, 1968. The reality, as the shooting massacre that killed U.S. District Judge John Roll and injured Arizona Rep. Gabrielle Giffords reminded us, is that there is a reason we still take the threat of politically motivated violence seriously. The pace may have slowed, but assassinations still happen in America.

On the 17th of January, a little more than a week after the tragedies in Arizona, police in Spokane, Wash., stopped a similarly heinous plot to kill those marching with the NAACP to commemorate the legacy of Dr. King.

As police would later determine, 36-year-old Kevin Harpham allegedly dropped a backpack on a bench in downtown Spokane. The pack contained a sophisticated homemade bomb filled with shrapnel dipped in cyanide. It was set to explode just as hundreds of marchers would be going by. Thankfully, a sharp-eyed cleanup-crew member spotted the bomb just moments before the crowds reached the bench, and a bomb squad acted quickly to defuse it.

The attempted bombing was one of several threats targeted at civil and human rights activists in the past 12 months. These include dozens of threats received by NAACP staff and volunteers in the days after we called on the Tea Party to police racist rhetoric at its rallies. In one such incident, a caller threatened to make "the streets run red" with our blood. It came less than a month after police shot an armor-clad gunman on his way to attack the ACLU and the Tides Foundation.

At bottom, while the location and the tactics change, the intent of these threats and attacks is always the same: to intimidate, to quell, to silence, to scare.

For 102 years, the parents and elders in the NAACP have responded to numerous threats against and assassinations of our leaders by quietly teaching our young people how to identify their fear, name it and keep on in spite of it.

It is a history that reaches all the way back to the freedmen and freedwomen who got us going during the early, blood-soaked days of Jim Crow. It is the tradition of cultivating young leaders in which King was raised. And it is this tradition, perhaps more than anything else, that allows us to keep bending the moral arc of this country toward justice.

Today is the anniversary of King's assassination, and the NAACP is leading more than 40 actions across the country. Each is part of the "We Are One" effort to draw attention to the spate of attacks on basic civil rights being committed by Tea Party-backed politicians in dozens of states.

These include attacks on everything from the right to organize to equal opportunity in education to a woman's right to choose to the rights of immigrants to be treated with basic dignity and respect. And while the Tea Party has become more inclusive in recent months, its rhetoric still often encourages the worst in those who aim to see our country move backward, not forward.

We stand up today. We will not be intimidated, we will not be silenced and we will fight anyone who attempts to strip away the rights of our fellow Americans until we win. It is this tradition of actively defending the rights and freedoms of all Americans that our tradition of raising courageous children ultimately protects.